A double-blind study of the effects of neomycin on hearing is being conducted in patients with Type II Hyperlipidemia. Patients are receiving oral neomycin and dietary regulation in rotation and/or combination. Audiologic examinations establishing baseline data are followed by monthly evaluation of pure tone thresholds and speech recognition measures in ipsilateral noise. At three month intervals, complete audiometric and tympanometric assessments are performed. Data indicate that no significant hearing losses have occurred in the patients under study.